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As someone that has only dabbled in Rust, the post reminds me of C++ and its mind-boggling templating system. Rust even seems to provide you with the multi-page

by koyote 4y ago

As someone that has only dabbled in Rust, the post reminds me of C++ and its mind-boggling templating system. Rust even seems to provide you with the multi-page compile errors. Is it really as bad, or does the post only highlight the misery you get when you're working on the fringes of what the language is capable of doing?

crabbygrabby 4y ago
It's actually really fun once you get the hang of it and realize the compiler is there to help you ship code that runs! This person hit a rough spot and got very frustrated basically... It happens, it's part of learning. The hardest thing about rust is, it tells you straight up when you don't understand something you are trying to do. For people who are otherwise productive and think they know certain things, this can be an ego slap. In return it makes you a better programmer because you learned something, it's just a bitter pill sometimes. In my opinion this person should have gone to rust discord/discourse, and asked for help. A lot of this would have been explained. Some of what they dealt with are rough edges that require practice to overcome though. But yea, lots of people are happily shipping async code in rust, right now. It's very possible.
- fulafel 4y ago
  Though most people don't get the hang of it. Some people also get into C++ templates and build complicated things with them for fun (eg the whole subfield of template metaprogramming came from inventing a clever abuse of the accidental power of templates as a poor man's macro system)
estebank 4y ago
> Rust even seems to provide you with the multi-page compile errors. rustc strives to provide you as much relevant context as possible. When hitting very verbose output, it is a hint that what you're trying to do is difficult and will require considered design that the compiler can't help you with. The compiler is trying to help you clarify your code so that it can understand it. Looking at the diagnostics shown in the blogpost, I see only one that is indeed terrible[1], but those in particularly are getting less and less verbose as we tackle them one by one with more targeted diagnostics. I also see the lifetime errors (the closure one when you specify the argument type and the on "`Execute` impl is not general enough"), which I wish gave more context. As support for HRTBs lands, related errors will stop happening as much and the code will indeed work (or the compiler will be able to tell you what alternative syntax you should be using). And, in a general plea for people writing Rust, when you encounter a subpar diagnostic, file a ticket[2]. [1]: https://hirrolot.github.io/media/rust-is-hard-or-the-misery-of-mainstream-programming/teloxide-error.txt https://hirrolot.github.io/media/rust-is-hard-or-the-misery-... Be aware that this is not exactly what rustc outputs, as some text decoration have been stripped, but that is a lot of text. [2]: https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Aopen+label%3AA-diagnostics https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Ao...
tialaramex 4y ago
For me the notable difference is that the Rust compile errors are almost always about the problem I actually have. They can be quite verbose, but that's largely from showing me what the problem is exactly. e.g. Rustc will show you where you borrowed X and then where you tried to modify it after forgetting it was borrowed, not just go "You can't do that, it's already borrowed" and expect you to figure out where and how or fly into a rage because you're sure you didn't borrow it. The error[E0308] mismatched type message with a type whose name repeats itself several times is a bad sign, yeah, you probably should not make a type like that. But most of the rest look like helpful Rust errors to me.
- estebank 4y ago
  To be fair, async (and generators, closures and Iterator) can expand to fairly hairy types with innocuous looking code. A think I do to simplify the output is to rely on `impl Trait` or `Box<dyn Trait>` to erase the type at strategic points, but that's working around my inability to find a way to make rustc figure out whether the full type is relevant or not right now.
jandrewrogers 4y ago
C++ templates are an inscrutable nightmare, the reputation is deserved. Rust is a bit different. Any software engineer that doesn't have a love/hate relationship with C++ templates is lying. On one hand they are extremely opaque and not user friendly, unnecessarily so. On the other hand, mastery of that dark art allows metaprogramming that you could only dream of in other systems languages -- the modern C++ template facility is extremely powerful. The number of C++ software engineers that achieve this level of metaprogramming mastery is quite small. In fairness, the C++ language has been intentionally evolving to make metaprogramming much easier than it used to be, and it has made massive strides in that direction. Rust lacks the expressiveness of C++ template metaprogramming facilities in significant ways. However, it is plausible that it will gain them eventually. The question is if it is possible to support advanced metaprogramming without the train wreck that is C++. I think it is eminently possible to do better, the question is how long it will take other systems languages to have metaprogramming expressiveness similar to current incarnations of C++.
- newuser46547 4y ago
  >mastery of that dark art allows metaprogramming that you could only dream of in other systems languages Can you give an example for this?
  - ainiriand 4y ago
    Unreal Engine vs Unity. Unreal Engine has a visual editor that allows the developers to accomplish most task without the need of entering the code editor thanks to a visual scripting language, it mirrors the C++ counterpart 100%. I believe it is not possible to do that in C# (Unity language).
    - pjmlp 4y ago
      Unity is in the process of achieving parity via Unity Visual Scripting.
- zozbot234 4y ago
  Rust supports compile-time metaprogramming via macros.

by koyote 4y ago

crabbygrabby 4y ago

It's actually really fun once you get the hang of it and realize the compiler is there to help you ship code that runs! This person hit a rough spot and got very frustrated basically... It happens, it's part of learning. The hardest thing about rust is, it tells you straight up when you don't understand something you are trying to do. For people who are otherwise productive and think they know certain things, this can be an ego slap. In return it makes you a better programmer because you learned something, it's just a bitter pill sometimes. In my opinion this person should have gone to rust discord/discourse, and asked for help. A lot of this would have been explained. Some of what they dealt with are rough edges that require practice to overcome though. But yea, lots of people are happily shipping async code in rust, right now. It's very possible.

fulafel 4y ago
Though most people don't get the hang of it. Some people also get into C++ templates and build complicated things with them for fun (eg the whole subfield of template metaprogramming came from inventing a clever abuse of the accidental power of templates as a poor man's macro system)

estebank 4y ago

> Rust even seems to provide you with the multi-page compile errors. rustc strives to provide you as much relevant context as possible. When hitting very verbose output, it is a hint that what you're trying to do is difficult and will require considered design that the compiler can't help you with. The compiler is trying to help you clarify your code so that it can understand it. Looking at the diagnostics shown in the blogpost, I see only one that is indeed terrible[1], but those in particularly are getting less and less verbose as we tackle them one by one with more targeted diagnostics. I also see the lifetime errors (the closure one when you specify the argument type and the on "`Execute` impl is not general enough"), which I wish gave more context. As support for HRTBs lands, related errors will stop happening as much and the code will indeed work (or the compiler will be able to tell you what alternative syntax you should be using). And, in a general plea for people writing Rust, when you encounter a subpar diagnostic, file a ticket[2]. [1]: https://hirrolot.github.io/media/rust-is-hard-or-the-misery-of-mainstream-programming/teloxide-error.txt https://hirrolot.github.io/media/rust-is-hard-or-the-misery-... Be aware that this is not exactly what rustc outputs, as some text decoration have been stripped, but that is a lot of text. [2]: https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Aopen+label%3AA-diagnostics https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Ao...

tialaramex 4y ago

For me the notable difference is that the Rust compile errors are almost always about the problem I actually have. They can be quite verbose, but that's largely from showing me what the problem is exactly. e.g. Rustc will show you where you borrowed X and then where you tried to modify it after forgetting it was borrowed, not just go "You can't do that, it's already borrowed" and expect you to figure out where and how or fly into a rage because you're sure you didn't borrow it. The error[E0308] mismatched type message with a type whose name repeats itself several times is a bad sign, yeah, you probably should not make a type like that. But most of the rest look like helpful Rust errors to me.

estebank 4y ago
To be fair, async (and generators, closures and Iterator) can expand to fairly hairy types with innocuous looking code. A think I do to simplify the output is to rely on `impl Trait` or `Box<dyn Trait>` to erase the type at strategic points, but that's working around my inability to find a way to make rustc figure out whether the full type is relevant or not right now.

jandrewrogers 4y ago

C++ templates are an inscrutable nightmare, the reputation is deserved. Rust is a bit different. Any software engineer that doesn't have a love/hate relationship with C++ templates is lying. On one hand they are extremely opaque and not user friendly, unnecessarily so. On the other hand, mastery of that dark art allows metaprogramming that you could only dream of in other systems languages -- the modern C++ template facility is extremely powerful. The number of C++ software engineers that achieve this level of metaprogramming mastery is quite small. In fairness, the C++ language has been intentionally evolving to make metaprogramming much easier than it used to be, and it has made massive strides in that direction. Rust lacks the expressiveness of C++ template metaprogramming facilities in significant ways. However, it is plausible that it will gain them eventually. The question is if it is possible to support advanced metaprogramming without the train wreck that is C++. I think it is eminently possible to do better, the question is how long it will take other systems languages to have metaprogramming expressiveness similar to current incarnations of C++.

newuser46547 4y ago
>mastery of that dark art allows metaprogramming that you could only dream of in other systems languages Can you give an example for this?
- ainiriand 4y ago
  Unreal Engine vs Unity. Unreal Engine has a visual editor that allows the developers to accomplish most task without the need of entering the code editor thanks to a visual scripting language, it mirrors the C++ counterpart 100%. I believe it is not possible to do that in C# (Unity language).
  - pjmlp 4y ago
    Unity is in the process of achieving parity via Unity Visual Scripting.
zozbot234 4y ago
Rust supports compile-time metaprogramming via macros.